Communication system having a community wireless local area network for voice and high speed data communication

ABSTRACT

A system ( 100 ) and method for providing high capacity voice and high speed data communication between user equipment terminals (UEs  104 ) and a public network ( 108 ). Generally, the system ( 100 ) includes a community Wireless Local Area Network (WLAN  102 ) having a centralized base transceiver station (CBTS  114 ) coupled to a public network ( 108 ), and several remote transceiver stations (RTSs  118 ) each coupled to several UEs ( 104 ), and, via a radio link, to the CBTS. In one embodiment, the CBTS ( 114 ) and RTSs ( 118 ) include a Global Systems for Mobile communication/General Packet Radio Service (GSM/GPRS) transceiver ( 148, 154 ) to provide data communication, and a WLAN transceiver ( 150, 156 ) to provide voice communication. Preferably, the WLAN transceiver ( 150, 156 ) is compatible with an open standard, such as IEEE 802.11. More preferably, the CBTS ( 114 ) and RTSs ( 118 ) include frequency converters ( 152, 158 ), to up-convert a frequency of signals generated in at least one of the transceivers to couple the CBTS to the RTS via a signal at a frequency above standard GSM frequencies.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/655,152, entitled Communication System Having a Community WirelessLocal Area Network for Voice and High Speed Data Communication, filedSep. 3, 2003, now abandoned which is a Continuation of U.S. patentapplication Ser. No. 10/342,591 entitled Communication System Having aCommunity Wireless Local Area Network for Voice and High Speed DataCommunication, filed Jan. 14, 2003, now abandoned which claims thepriority to U.S. Provisional Application Ser. No. 60/353,815, entitledCommunication System Having a Community Wireless Local Area Network forVoice and High Speed Data Communication, filed Jan. 31, 2002, which isincorporated herein by reference.

FIELD

The present invention relates generally to communication systems, andmore particularly to a communication system including a communityWireless Local Area Network (WLAN) to provide voice and datacommunication between a number of user equipment terminals and a publicnetwork via the community WLAN, and a method for using the same.

BACKGROUND

The use of communication networks and devices, including telephones,pagers, facsimile machines, computers and network access appliances, hasincreased exponentially in recent years. In many areas and communities,this increased demand for voice and data communication services hasoutpaced the growth in the public infrastructure required to supportthese services.

One possible solution to the above problem is the use of conventionalpublic or private wireless networks. However, this approach is notwholly satisfactory for a number of reasons. A fundamental drawback tothe use of conventional wireless networks is the cost associated withradios or user equipment terminals (UEs) capable of communicating withconventional GSM (Global Systems for Mobile communication), GPRS(General Packet Radio Service) or 3G (third generation cellular)wireless networks. Although the expense of these UEs is generally notborne by a service provider of a wireless network providing voice and/ordata communication to a community, it will be appreciated that highercosts translates to fewer potential subscribers. Thus, it is less likelythe service provider would be willing to bear the expense of installingnecessary base stations and switching centers in the community.

Another problem in areas or communities that are under served by anexisting wireless network, is the difficulty and expense of scaling thenetwork to provide services to additional users or additional services.For example, the typical approach used by wireless network serviceproviders to provide increased capacity, is to install additional basestations and switching centers. As noted above, due to the expense thisis unacceptable in certain rural or impoverished areas and communities.Moreover, this is also unacceptable in many developed and urban areas,where overcrowding of the licensed frequency bands leads to diminishingincreases in capacity for additional base stations and switching centersdue to interference with overlapping base stations.

Accordingly, there is a need for an inexpensive communication system andmethod of operating the same, that are capable of providing voice andhigh speed data communication to users in communities hitherto un-servedor under served by conventional communication systems. There is afurther need for a communication system and method of operating the samethat can be quickly and inexpensively scaled up to provide service toincreasing numbers of users. There is a still further need for acommunication system and method of operating the same that provides ahigh capacity for voice and data communication.

The system and method of the present invention provides these and otheradvantages over the prior art.

SUMMARY

It is an object of the present invention to provide a communicationsystem having capable of providing high capacity voice and high speeddata communication between a number of user equipment terminals (UEs)and a public network via a community Wireless Local Area Network (WLAN).

In one aspect the invention is directed to a communication system forproviding voice and data communication between a public network and anumber of UEs. Generally, the communication system includes a communityWLAN having a centralized base transceiver station (CBTS) coupled to thepublic network, and a number of remote transceiver stations (RTSs) eachcoupled to a number of the UEs, and, via a radio link, to the CBTS.Preferably, the public network includes a public switched telephonenetwork and the Internet, and the CBTS is coupled to the public networkvia a trunk. Alternatively, the CBTS may be coupled to the publicnetwork via a satellite link or other public wireless network.

In one embodiment, the CBTS and each RTS includes a Global Systems forMobile communication/General Packet Radio Service (GSM/GPRS) transceiverto provide data communication between the public network and the UEs,and a WLAN transceiver to provide voice communication between the publicnetwork and the UEs. The WLAN transceiver is compatible with an openstandard protocol, for example, HIgh Performance Local Area Network(HiperLAN/1), HIgh Performance Local Area Network (HiperLAN/2), andInstitute of Electrical and Electronics Engineers 802.11 (IEEE 802.11).

In another embodiment, the CBTS and each RTS includes a frequencyconverter, to up-convert a frequency of signals generated in at leastone of the transceivers in the CBTS and the RTS to couple the CBTS tothe RTS via a radio signal at a frequency above a standard GSM frequencyband of about 900 Mhz. Preferably, the CBTS and RTSs are adapted tocommunicate using GSM technology at a frequency band within (ETSI)specification. More preferably, the CBTS and RTSs are adapted tocommunicate using GSM technology at a frequency band of at least about3.5 Ghz.

In another aspect, the invention is directed to a transceiver stationfor use in a communication system. Generally, the transceiver stationincludes an antenna, a Global Systems for Mobile communication (GSM)transceiver, and a frequency converter coupled between the GSMtransceiver to enable communication using GSM technology at a frequencyabove conventional GSM frequency bands. Preferably, the transceiverstation is adapted to communicate using GSM technology at a frequencyband within (ETSI) specification. More preferably, the transceiverstation is adapted to communicate using GSM technology at a frequencyband of at least about 3.5 Ghz.

In one embodiment, the GSM transceiver is a GSM/General Packet RadioService (GSM/GPRS) transceiver, and the transceiver station is adaptedto communicate data as well as voice.

In yet another aspect, the invention is directed to a method ofproviding voice and data communication between a number of UEs and apublic network, using a communication system including a community WLAN.Generally, the method includes steps of: (i) receiving call informationin the community WLAN; (ii) providing subscriber identification andsecurity information for the UE to the community WLAN; and (iii)coupling the UE to the public network over the community WLAN.

In one embodiment, the public network includes a public switchedtelephone network and the Internet, and the step of coupling the UE tothe public network involves coupling the CBTS to the public network viaa trunk. Alternatively, the CBTS may be coupled to the public networkvia a satellite link or other public wireless network.

In another embodiment, the CBTS and each RTS includes a Global Systemsfor Mobile communication/General Packet Radio Service (GSM/GPRS)transceiver, and the step of coupling the UE to the public network isaccomplished by coupling the CBTS to the RTS using a GSM standard toprovide data communication between the public network and the UEs. Inone version of this embodiment, the CBTS and each RTS further includes aWLAN transceiver, and the step of coupling the UE to the public networkinvolves coupling the CBTS to the RTS using a WLAN standard to providevoice communication between the public network and the UEs. Preferablythe WLAN standard is an open standard protocol, such as the HIghPerformance Local Area Network (HiperLAN/1) standard, the HiperLAN/2standard, or an Institute of Electrical and Electronics Engineers 802.11(IEEE 802.11) standard.

In yet another embodiment, the CBTS and each of the RTSs includes afrequency converter, and the step of coupling the UE to the publicnetwork includes the step of up-converting a frequency of a signalgenerated in at least one of the GSM/GPRS and the WLAN transceivers tocouple the CBTS to the RTS via a radio signal at a frequency above astandard GSM frequency band of 900 Mhz. Preferably, the step ofup-converting the frequency of the signal involves up-converting thefrequency of the signal to a frequency band within (ETSI) specification.More preferably, the step of up-converting the frequency of the signalinvolves up-converting the frequency of the signal to a frequency bandof at least about 3.5 Ghz.

Advantages of the apparatus and method of the present invention include:low cost to manufacture and install; high speed transmission of data, upto 54 to 100 Mbps; high capacity for voice and data communication; andeasy scalability since, an 802.11 based WLAN, for example, permits up to256 RTSs per CBTS.

It is also an object of the present invention to provide a communicationsystem that bridges the gap between an existing public network and WLANsto provide authentication and roaming capabilities of the former withthe high-speed and high-bandwidth of the latter.

It is a further object of the present invention to provide acommunication system in which a UE terminal of a WLAN operating in anunregulated frequency band is able to access a public network, such as apublic switched telephone network, a public GSM cellular network, public3G network, or the Internet, and/or a private network, such as a privatecellular network, a campus or enterprise 3G network, or a private branchexchange (PBX) with a functionality and capabilities similar to thoseavailable from mobile stations of more expensive GSM cellular networksand 3G cellular networks.

It is a still further object of the present invention to provide acommunication system in which GSM/GPRS/3G broadband services areprovided using WLAN broadband technology and in particular using 802.11based technology.

In one aspect, the present invention is directed to communication systemwhich enables a user to access a public network through low poweredunregulated user equipment terminals (UEs) or transceivers. Generally,the communication system includes a public cellular network and awireless local area network (WLAN) coupled to the public cellularnetwork, the WLAN configured to facilitate communication between the UEsand the public cellular network. The public cellular network can be aglobal system for mobile communications (GSM) network coupled to apublic switched telephone network (PSTN). Alternatively, the publiccellular network can further include a third-generation mobilecommunications (3G) network coupled to the GSM network and to theInternet. Optionally, the communication system further includes aprivate cellular network coupled to the WLAN to facilitate communicationbetween the UEs and mobile stations associated with the private cellularnetwork.

In one embodiment, the communication system further comprises a RemoteAuthentication Dial In User Service (RADIUS) server to authenticate UEsaccessing the communication system through the WLAN and to authorizeaccess to the communication system. Where the communication systemincludes multiple linked WLANs, a home location registry (HLR),including, for example, a home location register and/or a homesubscription sever, and visitor location registry (VLR) coupled to theRADIUS server provide roaming capabilities for the UEs among theplurality of WLANs.

In another embodiment, the UE includes a computer program to enable itto access and control supplementary services and/or value-added servicesprovided by the public and/or private network. Supplementary servicesinclude, for example, Voice Group Call Service, Voice Broadcast Service,Service definition Line Identification Supplementary Services, CallForwarding Supplementary Services, Call Waiting and Call HoldSupplementary Services, Multiparty call conferencing, Closed User GroupSupplementary Services, Advice of Charge Supplementary Services, CallBarring Supplementary Services, Unstructured Supplementary Service Data,Explicit Call Transfer, Completion of Calls to Busy Subscriber, ShortMessage Service, and Follow Me. Value-added services include, forexample, e-mail, calender, and wireless inventory, etcetera.

Preferably, the WLAN is compatible with one or more high performancewireless communication standards. For example, a EuropeanTelecommunications Standards Institute (ETSI) standard for BroadbandRadio Access Networks (BRAN), such as a high performance local areanetwork (HiperLAN/1), HiperLAN/2, or a high performance MetropolitanAccess Network (HiperMAN). Other examples, include Institute ofElectrical and Electronics Engineers 802.11 standards (IEEE 802.11),such as 802.11(a) and 802.11(b).

A communication system according to the present invention isparticularly useful to operators of hotels, hotel chains, airports,airport building maintenance, and other like enterprises for deploymentof in-building broadband RF services, or for users of UEs with e-mailmessaging capabilities.

In another aspect, the present invention is directed to a method ofenabling a number of UEs to communicate with a public network and/orprivate network via the WLAN. Generally, the method includes steps of:receiving in the WLAN call information to or from one of the number ofUEs; providing subscriber identification and security information forthe UE to an authentication server; and coupling the UE to the publicnetwork or private network over the WLAN.

Preferably, the communication between the UEs and the public cellularnetwork facilitated by the WLAN includes voice communication. Morepreferably, the UE further includes computer program necessary to accessor control supplementary services and/or value added services providedby the public network or private network, and the method furtherincludes the step of controlling such supplementary services and/orvalue added services.

In one embodiment, the UE further includes a memory system havingsubscriber identification and security information stored therein, andthe step of providing subscriber identification and security informationfor the UE to the authentication server is accomplished by providingsubscriber identification and security information associated from thememory system. Alternatively, the UE further includes or is coupled to acard holder/reader holding a number of GSM-type SIM cards or 3G-typeUSIM cards, and the step of providing subscriber identification andsecurity information for the UE to the public cellular network involvesreading subscriber identification and security information stored in oneof the cards held in the card holder/reader, which may be public networkor private network subscription identifiers, or a combination of bothpublic and private subscription data.

The communication system and method of the present invention isparticularly useful in public cellular network including a GSM networkcoupled to a PSTN and/or a 3G-network coupled to a GSM network, to thePSTN and/or to the Internet. The communication system and method providea means for coupling an 802.11 network coupled to the GSM network andthe 3G-network to facilitate communication between a number of UEs andthe public cellular network. Generally, the communication systemincludes means for authenticating and authorizing access to the system.The means for authenticating and authorizing access can include a RADIUSsystem or server coupled to the communication system through aVLR/RADIUS interface.

BRIEF DESCRIPTION OF THE FIGURES

These and various other features and advantages of the present inventionwill be apparent upon reading of the following detailed description inconjunction with the accompanying drawings, where:

FIG. 1A is a block diagram of a communication system including acommunity Wireless Local Area Network (WLAN) according to an embodimentof the present invention;

FIG. 1B is a block diagram of an alternative embodiment of thecommunication system of FIG. 1A;

FIG. 1C is a block diagram of another alternative embodiment of thecommunication system of FIG. 1A;

FIG. 2 is a block diagram of a Centralized Base Transceiver Station(CBTS) of a community WLAN according to an embodiment of the presentinvention;

FIG. 3 is a block diagram of one of a plurality of Remote TransceiverStations (RTSs) of a community WLAN according to an embodiment of thepresent invention;

FIG. 4 is a flowchart showing an embodiment of a process according tothe present invention for providing voice and data communication betweena plurality of User Equipment terminals (UEs) and a public network via acommunity WLAN;

FIG. 5 is a block diagram of a communication system according to anembodiment of the present invention having a private network including awireless local area network (WLAN) coupled to a private cellular networkand a private branch exchange, and a public network having a publicglobal system for mobile communications (GSM) network and a publicthird□generation mobile communications (3G) network;

FIG. 6 is a block diagram of a communication system including aHiperLAN, HiperMAN, and 802.11 WLANs coupled to a private cellularnetwork and a public network, and a Remote Authentication Dial In UserService (RADIUS) server coupling the WLAN to public and private homelocation registries (HLRs) according to an embodiment of the presentinvention;

FIG. 7 is a block diagram of a portion of the communication system ofFIG. 6 illustrating the coupling of the RADIUS server to an accesspoint, a user equipment terminal (UE), and the private HLR, according toan embodiment of the present invention;

FIG. 8 is a block diagram of a communication system including an 802.11WLAN coupled to a private cellular network and a public network, and aRADIUS server according to an embodiment of the present invention;

FIG. 9 is a flowchart showing an embodiment of a process for enablingUEs to communicate with a private cellular network and a public networkvia a WLAN according to an embodiment of the present invention;

FIG. 10 is a block diagram of a communication system including acorporate LAN coupled to the public network through a WLAN according toan embodiment of the present invention;

FIG. 11 is a block diagram of an alternative embodiment of thecommunication system of FIG. 10, having multiple RADIUS servers,authentication servers and clients according to the present invention;

FIG. 12 is a block diagram of an embodiment of a communication systemhaving distributed private HLR and authentication server according tothe present invention for enabling roaming of UEs;

FIG. 13 is a block diagram of yet another embodiment of a communicationsystem including multiple corporate LANs according to the presentinvention;

FIG. 14 is a block diagram showing communication routing in acommunication system including a WLAN and a RADIUS server according tothe present invention; and

FIG. 15 is a block diagram showing an embodiment of architecture of acommunication system according to the present invention.

DETAILED DESCRIPTION

The present invention is directed to a communication system and methodfor providing high capacity voice and high speed data communicationbetween a number of user equipment terminals (UEs) and a public networkvia a communication system including a community Wireless Local AreaNetwork (WLAN).

A communication system according to the present invention will now bedescribed with reference to FIG. 1A. FIG. 1A is an exemplary blockdiagram of a communication system having a community WLAN to couple anumber of user equipment terminals (UEs) to a public network accordingto an embodiment of the present invention. For purposes of clarity, manyof the details of communication systems and in particular of publicnetworks that are widely known and are not relevant to the presentinvention have been omitted.

Referring to FIG. 1A, the inventive communication system 100 includes acommunity WLAN 102 to provide access for a number of UEs 104 at a numberof different building or sites 106 to a public network 108 including apublic switched telephone network (PSTN 110) and the Internet 112.

Generally, the community WLAN 102 includes a centralized basetransceiver station (CBTS 114) coupled the public network via a landlineor trunk 116, such as an E1 or T1 trunk. The CBTS 114 also couples via aradio link to a number of remote transceiver stations (RTS 118),generally one RTS permanently installed or fixed at each site 106, eachof which in turn couples to a number of UEs 104, such as telephones 120,fax machines 122 and computers 124, to provide access to the publicnetwork 108 for voice or data communication. Each of the UEs 104 withina particular site 106 can be directly connected to the RTS 118 through adedicated connection, or can be connected through a local area network(LAN 126), such as an Ethernet, 100Base T, Fast Ethernet or GigabitEthernet, at the site.

In a preferred embodiment, the community WLAN 102 further includes aprivate home location registry/authentication server (HLR/AuC 128)coupled to the CBTS 114 for recording and storing information relatingto users or subscribers of the community WLAN. In operation, a RTS 118or a UE 104 first introduced into an area served by the community WLAN102 must provide authentication or authorization information to theHLR/AuC 128. Generally, the authentication/authorization is provided ina manner similar to that of a Global Systems for Mobile communication(GSM) mobile station in a conventional GSM wireless network. There areseveral are several ways of accomplishing this: (i) each UE 104 can beprovided with a subscriber identity module (SIM) cards similar to thosecards commonly found in GSM mobile stations; (ii) each RTS 118 can beprovided with a number of SIM cards which it can associate with the UEs104 on a permanent or temporary basis; or (iii) each RTS can be coupledto a memory system in which is stored subscriber identification andsecurity information that constitutes a virtual SIM (VSIM), described ingreater detail in commonly assigned, co-pending U.S. patent applicationSer. No. 10/002,551, which is incorporated herein by reference.

Use of the HLR/AuC 128 and SIMs enables generation and recording of calldetail records (CDRs) for billing purposes, facilitates incomingcommunication from the public network 108, and allows communicationbetween UEs 104 at different sites 106 with the community WLAN 102service area.

Optionally, the community WLAN 102 also include a visitor locationregistry (VLR) (not shown) to maintain subscriber information forvisitors or roamers to the cell or area served by the community WLAN.

FIG. 1B shows an alternative embodiment of the communication system 100of FIG. 1A, in which the CBTS 114 is coupled to the PSTN 110 and theInternet 112 through a public network 108 further comprising a publicwireless network including a base station controller (BSC 130) and amobile switching center (MSC 132). This embodiment, may be particularlyuseful in under served areas or communities in which a demand forcommunication services has outstripped the capacity of an existingwireless or wired communication system (not shown).

FIG. 1C shows another alternative embodiment of the communication system100 of FIG. 1A, in which the CBTS 114 is coupled to the PSTN 110 and theInternet 112 through a satellite radio link via a satellite 134. Thisembodiment, may be particularly useful in areas or communities hithertounserved by conventional wireless or wired communication s systems (notshown).

The major components of the community WLAN 102, that is the CBTS 114 andthe RTSs 118, will now be described in greater detail with reference toFIGS. 2 and 3.

Referring to FIG. 2, preferably the CBTS 114 is a complete stand-aloneNetwork-In-a-Box (NIB), such as a WAVEXpress NIB platform, commerciallyavailable from Interwave Communications, of Menlo Park, Calif.Generally, the CBTS 114 includes within a single enclosure 136: (i) apower supply 138; (ii) a number of plug-in-modules or cards 140,including a number of radio frequency (RF) transceivers forcommunicating with the RTSs 118; (iii) an RF combiner 142 for combiningsignals to and/or from the multiple transceivers; (iv) an RF poweramplifier 144 for amplifying received and/or transmitted signals; and(v) an antenna 146. Preferably, the cards 140 include at least oneGSM/GPRS transceiver 148 capable of providing data communication betweenthe public network 108 and the UEs 104 using GSM standard or technology.More preferably, the cards 140 also include at least one WLANtransceiver 150 capable of capable of providing data communication tothe UEs 104 using an open standard protocol, such as the HIghPerformance Local Area Network (HiperLAN/1) standard, the HiperLAN/2standard, or an Institute of Electrical and Electronics Engineers 802.11(IEEE 802.11) standard. Most preferably, both the GSM/GPRS transceiver148 and the WLAN transceiver 150 are capable of non-line of sight (NLOS)operation. That is they are capable of communicating with RTSs 118 thatare obscured or shielded from the CBTS 114 by intervening vegetation,buildings or terrain.

In addition, the cards 140 can include a number of cards or module forinterfacing with the HLR/AuC 128, and the trunk 116 to connecting to thepublic network 108. For example, the cards 140 can include an E1 card,T1 card or an ICP card.

Optionally, in accordance with another aspect of the present invention,the CBTS 114 further includes a frequency converter 152 to enable theCBTS to communicate with the RTSs 118 using the GSM standard with asignal having a frequency up-converted from a frequency bandconventionally used in GSM systems or networks, thereby tapping into anunused or underused portion of the radio spectrum and increasingcapacity of the community WLAN 102 and avoiding restrictions ontransmission rates. Preferably, the

frequency of the signal is up-converted to a frequency band within thespecification developed by the European Telecommunications StandardsInstitute (ETSI) for GSM communication. More preferably, the frequencyof the signal is up-converted to a frequency band of at least about 3.5Ghz.

Referring to FIG. 3, the RTSs 118 generally include: (i) a power supply151; (ii) at least one GSM/GPRS transceiver 154; (iii) a WLANtransceiver 156; (iv) a frequency converter 158; and (v) an antenna 159.Additionally, depending on the UEs 104 coupled to a particular RTS 118and the manner in which they are coupled, the RTS can further include anumber of interfaces or modules (not shown) for interfacing with theUEs. Such interfaces can include for example, TCP/IP interfaces,ethernet interfaces and SCSI interfaces.

A process or method for operating communication system 100 according toan embodiment of the present invention will now be described withreference to FIG. 4. FIG. 4 is a flowchart showing an embodiment of amethod for providing voice and data communication between the UEs 104and the public network 108 via the community WLAN 102. In the method,call information, from either one of the UEs 104 or from the publicnetwork, is received in the community WLAN 102 (step 160). Subscriberidentification and security information for the UE 104 is provided tothe community WLAN 102 by the UE and verified by the HLR/AuC 128 (step162). A frequency of signals generated in at least one of thetransceivers in the CBTS 114 and the RTS 118 is up-converted to couplethe CBTS to the RTS via a radio signal at a frequency above the standardGSM frequency band (step 164), and the UE 104 is coupled to the publicnetwork 108 over the community WLAN 102 (step 166).

In another aspect, the invention is directed to a communication systemand method for enabling UEs associated with a WLAN to communicate with apublic network.

A communication system according to the present invention will now bedescribed with reference to FIG. 5. FIG. 5 is an exemplary block diagramof a communication system having a WLAN coupled to a public networkincluding a GSM network and a 3G network according to an embodiment ofthe present invention. For purposes of clarity, many of the details ofcommunication systems and in particular of GSM networks and 3G-networksthat are widely known and are not relevant to the present invention havebeen omitted.

Referring to FIG. 5, the communication system 200 generally comprises apublic core network or public network 202 including a public cellularnetwork 204 with connections to a PSTN 206 and the Internet 208. Thepublic cellular network 204 can include a GSM 210 network forcommunicating with public MSs 212 and a 3G-network 214, such as a3G-UMTS (universal mobile telecommunications system), for communicatingwith public UEs 216. The public cellular network 204 typically furtherincludes a GPRS/3G-GPRS network 218.

The communication system 200 further includes a private network 220 witha private cellular network 222 for communicating with private MS 226, aWLAN 228 for communicating with private transceivers or UEs 230, and,optionally, a PBX 232 for communicating with PBX telephones 234. In oneembodiment, the private cellular network 222 includes at least oneWAVEXchange™ (WXC) or a Network-In-A-Box™ (NIB 224) commerciallyavailable from interWAVE Communications Inc., of Menlo Park, Calif. AWXC generally includes a MSC, a built-in VLR/HLR. The NIB 224 includes aMSC, a BSC and a BTS in a single enclosure. The private cellular network220 is coupled to the GSM network 210, the GPRS network 218, and the3G-network 214 of the public cellular network 204 through a number orinterface functions or links, described in more detail below.

In accordance with the present invention, the WLAN 228 is coupled to thepublic network 202 through the NIB 224 and is adapted to enable voiceand data communication between the private UEs 230 and the privatemobile stations 226, public mobile stations 212, public UEs 216, PBXtelephones 234, and telephones (not shown) coupled to the PSTN 206and/or the Internet 208. Access points (not shown in this figure) of theWLAN 228 can be coupled to the NIB 224 through a wired local areanetwork (LAN 229), such as an Ethernet, 100Base T, Fast Ethernet orGigabit Ethernet, or through a wireless or radio-link (not shown). Oneadvantage of the communication system 200 of the present invention isthe ability to enable communication between the public network 202 andless expensive, low-power, unregulated private UEs 230 while providingsubstantially the same functions and services available from much moreexpensive radios, MSs 212 or UEs 216 of the public cellular network 204and/or private cellular network 222.

It will be understood, that the communication system 200 can include anumber of private cellular networks 222, each with an associated WLAN228, and each linked by a private wide area network (PWAN) (not shown)to provide wireless or cellular type communication via a WLAN over anextended service area. This embodiment provides the further advantagesof the ability to avoid tolls and maintain ownership and control ofinformation transmitted between different sites of an enterprise linkedby the PWAN.

In another embodiment, the private UE 230 further includes coupledthereto a subscriber identity module (SIM 236) having an algorithm and akey to support authentication and encryption necessary to enable orfacilitate communication with the public network. 202 and/or privatecellular network 224. In one version of this embodiment, each private UE230 includes a card holder/reader (not shown in this figure) and one ormore GSM-type SIM cards or 3G-type USIM cards (not shown) held in thecard holder/reader, each SIM card subscriber identification and securityinformation stored therein for one or more user profiles, which mayinclude public network or private network subscription identifiers, or acombination of both public and private subscription data/identifiers.Alternatively, the SIM 236 encompasses subscriber identification andsecurity information stored in a memory system (not shown) of theprivate UE 230. This latter version has the advantage of enabling theSIM 236 to be downloaded from the WLAN 228 along with computer softwareor programs that enable the private UE 230 to emulate or function as acommunication terminal. Such emulator programs are described in greaterdetail in commonly assigned, co-pending U.S. patent application Ser. No.10/155,931, which is incorporated herein by reference.

In yet another embodiment, the private network 220 further includes anidentity module 238 coupled to the NIB 224, and having at least oneidentifier or virtual identifier stored therein that can be permanentlyor temporarily associated with one or more private UEs 230, to enablethe private UE to communicate with the public network 102 and/or theprivate cellular network 222 via the WLAN 228. Identity modules andvirtual identifiers and described in greater detail in commonlyassigned, co-pending U.S. patent application Ser. No. 10/002,551, filedNov. 1, 2001, which is incorporated herein by reference. Generally, thevirtual identifiers include algorithms and a key to supportauthentication and encryption necessary to facilitate communication withthe public network 102 or private cellular network 222. In one versionof this embodiment, the identity module 238 includes subscriberidentification and security information stored in a memory system (notshown) coupled to the NIB 224. Alternatively, the identity module 138includes a card holder/reader (not shown), as described above, and thevirtual identifiers include one or more GSM-type SIM cards or 3G-typeUSIM cards held in the card holder/reader), as described above.

The virtual identifiers can be associated with the private UEs 230 on aone-to-one basis; on a one-to-many basis; or on a many-to-many basis inwhich the virtual identifiers are maintained as a pool of virtualidentifiers that are associated temporarily with a private UE on an asneeded basis. Alternatively, the virtual identifiers can be associatedwith the private UEs 230 on a many-to-one basis to provide a singleprivate UE with multiple different user profiles that can be selected bya user for record or billing purposes. For example, a user placing acall from a private UE 130 over the public cellular network 204 couldenter a first code selecting a first user profile when the call is forbusiness purposes, and a second when the call is for private purposes.In addition, the communication system 200 or the user can select aGSM-type SIM identifier (virtual SIM) when the communication is over theGSM network 210, and a 3G-type USIM identifier (virtual USIM) when it isconnected or routed over the 3G network 214.

Preferably, the SIM 234 or identity module 238, and programs or softwarein the private UE 230 that allow it to emulate a communication terminal,are also adapted to enable the private UE to control or accesssupplementary and/or value added services provided by the privatecellular network 222 or public network 202 service provider.Supplementary services can include, for example, Voice Group CallService; Voice Broadcast Service; Service definition Line IdentificationSupplementary Services; Call Forwarding Supplementary Services; CallWaiting and Call Hold Supplementary Services; multiparty SupplementaryServices including call conferencing; Closed User Group SupplementaryServices, Advice of Charge Supplementary Services; Call BarringSupplementary Services; Unstructured Supplementary Service Data;Explicit Call Transfer; Completion of Calls to Busy Subscriber; ShortMessage Service; and Follow Me. Value added services include, forexample, e-mail, calendar, and wireless inventory, etcetera.

The WLAN 228 can include one or more separate and discrete networks eachusing one of a number of different protocols including IEEE 802.11standards (802.11), and ETSI standards for BRAN, such HiperLAN orHiperMAN. These standards serve to ensure the interoperability ofwireless communications equipment operating in the same spectrum butmanufactured by different manufacturers. In particular, BRAN is a set ofcommunication standards for Broadband Radio Access Networks developed byETSI in response to growing market pressure for low-cost, high capacityradio link, and is used chiefly in European countries. BRAN providesbroadband wireless access at a rate of 25 Mbit/s or more to networks orWLANs operating in either licensed or license exempt spectrum. IEEE802.11 standards are a similar set of WLAN standards. There are twotypes of HiperLAN: (i) HiperLAN/1, which provides communications at upto about 20 Megabytes Per Second (Mbps) in the 5 GHz band; and (ii)HiperLAN/2, which provides communications at up to 54 Mbps in the sameband. HiperMAN is a similar standard used for systems serving ametropolitan area. Although, HiperMAN is generally used in largercommunication systems that could be defined as a wireless metropolitanarea network, rather than a WLAN, it will be appreciated that theprinciples of the present invention can be applied to such acommunication system. Accordingly, it will be understood that as usedherein the term WLAN refers to both wireless local area networks and awireless metropolitan area networks. IEEE 802.11 refers to a line ofrelated specifications or standards developed by the IEEE for wirelesscommunication, including 802.11, 802.11a, 802.11b, 802.11g and 802.1x.802.11 is similar to HiperLAN and applies to WLANs having from 1 or 2Mbps transmission rates in the 2.4 GHz band using either frequencyhopping spread spectrum (FHSS) or direct sequence spread spectrum(DSSS). 802.11a is an extension to 802.11 that applies to WLANs,provides up to 54 Mbps in the 5 GHz band, and uses an orthogonalfrequency division multiplexing encoding scheme rather than FHSS orDSSS. 802.11b, also known as 802.11 High Rate or WiFi, is anotherextension that provides up to 11 Mbps transmission rates in the 2.4 GHzband, allowing wireless functionality comparable to Ethernet. Thus,802.11b is particularly useful interfacing with or coupling to GPRSsystems according to the present invention for wireless transmission ofdata. 802.11g applies to WLANs and provides greater than 20 Mbps in the2.4 GHz band.

In still another embodiment, the WLAN 228 is further coupled to theInternet 208 through a firewall 240, to enable the private UE 230 totransfer video and audio data, and/or to transfer or download largefiles or attachments to or from other data processing systems orservers. Preferably, the private UE 230 is adapted to enable a user tosimultaneously carry on communication, for example voice communication,with a telephone or terminal in the private cellular network 222 orpublic network 202, and communication, for example data communication,with a terminal coupled to the Internet 208. More preferably, theprivate UE 230 includes a computer program to simultaneously enablevoice over an internet protocol network communication (VoIP), with atelephone or terminal (not shown) coupled to the Internet 208, WLAN 228,LAN 229 or another IP network. The VoIP program can include a standardVoIP program native to the private UE 230, which comes standard on manycomputers and portable computers, or a VoIP program included withcomputer software or programs downloaded from the WLAN 228, such as thevirtual SIM or emulator program, as described above.

In still another embodiment, computers or terminals 242 coupled to theNIB 224, through the LAN 229, are also adapted to communicate voice anddata with telephones or terminals in the public cellular network 204and/or private cellular network 222 via the NIB 224 and the interfacefunctions or links from the NIB to the public and private cellularnetworks 204, 222.

An embodiment of the communication system 200 of the present inventionwill now be described in greater detail with reference to FIG. 6.Referring to FIG. 6, the public network 202 includes a public HLR/VLR244 coupled to the GSM network 210 and the 3G-network 214. The publicHLR of the HLR/VLR 244, can include, for example, a home locationregister and/or a home subscription sever HSS, and records and storesinformation relating to users or subscribers of the public network. TheVLR of the HLR/VLR 244 maintains subscriber information for visitors orroamers to the cells or area served by the public cellular network 204.Generally, the HLR/VLR 244 also includes an authentication andaccounting server or function (not shown) used by many service providersto authorize access to the public GSM network 210 and/or the public3G-network 214.

The GSM network 210 includes a gateway mobile services switching center(GMSC 246) coupled to the PSTN 206 through a landline or trunk 248, andto the HLR/VLR 244 through a C interface or link 250. The GMSC 246 is agateway switching center or exchange that directs or routes calls fromthe PSTN 206 to the MSs 212, and from the MS to the PSTN. A thirdgeneration mobile services switching center (3G-MSC 252) coupled to theHLR 244 through a D interface or link 254 provides switching servicesand co-ordination between mobile stations 212 in the GSM network 210 andpublic UEs 216 in the 3G network 214. Optionally, the 3G-MSC 252 alsoinclude another or second VLR to maintain subscriber information forvisitors or roamers to the cells or area served by the 3G-MSC. The3G-MSC 252 also couples to one or more MSCs 256, only one of which isshown, through an E interface or link 258. As with the 3G-MSC 252, theMSC 256 can also include a VLR to maintain subscriber information forvisitors or roamers to the cell or area served by the MSC. The MSC 256in turn couples through an A interface or link 260 to one or more BSC262, each of which controls one or more BTS 264 through an Abisinterface or link 266. The MSC 156 also couples to the private cellularnetwork 222 through a private A-link intelligent multiplexor interfacefunction or link (PALIM 268). PALIM functions or links are describeddetail in commonly assigned U.S. Pat. Nos. 5,818,824, 5,734,699,5,999,813 and 6,212,395, all of which are incorporated herein byreference.

In the embodiment shown, the 3G-network 214 includes a third-generationgateway GPRS support node (3G-GGSN 270) coupled to the Internet 208through a Gi interface or link 272, and to the HLR 244 through a Gcinterface or link 274. The 3G-GGSN 270 provides an interface between the3G cellular network 214 and an IP network, such as the Internet 208. Athird generation serving GPRS support node (3G-SGSN 276) coupled to theHLR 244 through a Gr interface or link 278 and to the 3G-MSC 252 througha Gi link 280, handles data traffic in an area served by the 3G cellularnetwork 214. Optionally, the 3G-SGSN 276 is further coupled to a local,second generation (2G) or GPRS SGSN 282 through a Gn interface or link284 to provide an interface between the 3G cellular network 214 and theWLAN 228. The 3G-SGSN 276 also couples to one or more 3G radio networkcontrollers (3G-RNC 286), only one of which is shown, through an Iu-PSinterface or link 288. Each 3G-RNC 286 controls one or more Node Bs 190through an Iub interface or link 292. The 3G-RNC 286 also couples to the3G-MSC 252 through an Iu-CS interface or link 294 to providecommunication between the public UEs 216 and the MSs 212 of the GSMnetwork 210 or telephones (not shown) connected to the PSTN 206.

As shown in FIG. 6, and as noted above, the WLAN 228 can include one ormore separate and discrete networks or access points 228A, 228B, 228C,each using a number of different protocols including HiperLAN, HiperMANand 802.11, as described above. The particular network or protocol usedin the WLAN 228 can be selected based on factors including cost, desiredbandwidth or bit-rate, or required range, frequency and regulatorylimitations. For example, a communication system 200 in Europe or otherstates or nations adopting the HiperLAN standards might use theHiperLAN/1 or HiperLAN/2 standard depending on the desired bit-rate,while systems in the United States might use one of the 802.11standards. Communication systems 100 serving a metropolitan area orrequiring a higher capacity or bandwidth might use the HiperMANstandard.

As also shown in FIG. 6, the WLAN 228 can be coupled to the Internet 208and to a number of different components in the GSM network 210 and/orthe 3G-network 214. For example, in the 3G-network 214 the WLAN 228 canbe coupled to the 3G-GGSN 270 through the NIB 224 and via an IuPSWLANinterface or link 296, the GPRS SGSN 282 via an IuPSWLAN interface orlink 298, the 3G-RNC 186 via an IubisWLAN interface or link 300, and/orto one or more Node Bs 290 via a NodeBWLAN interface or link 302. In theGSM network 110 the WLAN 228 can be coupled to the BTS 268 via a BTSWLANinterface or link 304, to the BSC 262 via an AbisWLAN interface or link306, and/or to the MSC 256 via an AWLAN interface or link 308. Inaddition, the WLAN 228 can be coupled to the MSC 256 through the NIB 224and over the PALIM link 268, described above.

It will be understood that where the WLAN 228 includes multiple separatenetworks or access points 228A, 228B, 228C, which may or may not usedifferent protocols, each of the separate access points can be coupledthrough the NIB 224 to different components in the public network 202.For example, it might be desirable to couple an access point 228C usingan 802.11b standard for high speed transmission of data to the GPRS SGSN282.

In yet another embodiment, the communication system 200 further includesa Remote Authentication Dial In User Service (RADIUS) system 310, havinga RADIUS authentication and accounting gateway or server 312. The RADIUSsystem can be combined with the NIB 224, as shown, or can comprise astandalone RADIUS server 312 separate and distinct from the NIB. RADIUSis an authentication and accounting system used by many serviceproviders to authorize access to a communication system. Though not anofficial standard, the RADIUS specification is maintained by a workinggroup of the Internet Engineering Task Force (IETF). Generally, RADIUSrequires users to enter a username and password, which is passed to theRADIUS server 312 to check that the information is correct, andauthorize access to the communication system 200. A separateauthentication/authorization server (not shown in this figure) withinthe RADIUS system 310 or coupled to the RADIUS server 312 provides orsupports roaming capabilities for the private UEs 230 among theplurality of access points 228A, 228B, 228C and the public cellularnetwork 204. Additionally, the RADIUS server 312 receives accountingpackets or call detail records (CDRs) generated by the different accesspoints 228A, 228B, 228C, and forwards these accounting packets to abilling server (not shown) through a RADIUS proxy interface (not shown)to bill telecommunications charges to the appropriate parties.

Preferably, the RADIUS server 312 is coupled via a VRAD 314 to thepublic HLR/VLR 244 and, to a private HLR (PHLR 316) and/or private VLR(PVLR 318). The VRAD 314, private HLR 316 and private VLR 318 can becombined with the RADIUS system 310, as shown, or can comprise astandalone server separate and distinct from the RADIUS system. Forexample the VRAD 314, private HLR 316 and private VLR 318 can becombined with the NIB 224, and the system 310 or server 312 can beseparate and distinct from the NIB 224, as described above. The privateHLR 316 is stores information on UEs 230 registered or subscribing tothe communication system 200, and more particularly to the WLAN 228and/or the private cellular network 222. The private VLR 318 is capableof temporarily storing information on subscribers or UEs 230 consideredas roaming within the service area of the WLAN 228. The VRAD 314 is aVLR-RADIUS interface, and includes an internal integral VLR 320 and anextensible authentication protocol (EAP) interface 322 for signaling tothe public HLR/VLR 244 and the private HLR 316. The RADIUS server 312couples to the public HLR/VLR 244 via an EAP over RADIUS link(EAP/RADIUS Link 324). The RADIUS server 312 further couples to thepublic HLR/VLR 144 via the LAN 229 and the Internet 208 over an EAP overSIM link (not shown in this figure) for transmission of data. The RADIUSserver 312 couples to one or more access points 228A, 228B, 228C, viathe NIB 224 and the LAN 229.

The RADIUS server 312 supports roaming of private UEs 230 based on aRADIUS/DIAMETER roaming model along with traditional GSM subscriberroaming based upon the mobile application part (MAP) standard foraddress registration of roamers and inter-system hand-off procedures.Part of the SS7 protocol used in GSM, MAP standardizes addressregistration of roamers and inter-system hand-off procedures. In case ofa communication system 200 having a number of private cellular networks222, each with an associated WLAN 228 and linked by a PWAN (not shown),the RADIUS server 312 can act as a proxy to forward an authenticationrequest via the VRAD 314 to a single, central public HLR/VLR 244 and/ora single, central private HLR 316 Alternatively, where the communicationsystem 100 includes either a distributed public HLR/VLR 244 and/or adistributed private HLR 316, the RADIUS server 312 routes aninterpretation of either a username or a user identity provided in theauthentication procedure, to the appropriate public or private HLR. Inone version of this embodiment, the RADIUS server 312 is enhanced tocontact the appropriate or controlling public or private HLR 244, 314,either by: (i) querying a standalone Central Address Table server (notshown) coupled thereto to match International Mobile Subscriber Identity(IMSI) information provided in the authentication procedure to thecorresponding HLR; or (ii) using a configuration table that matches theIMSI ranges with the appropriate or controlling public or private HLR.This last model works well if IMSI partitioning is implicitly orexplicitly enabled for subscriber provisioning across multiple public orprivate HLR 244, 316.

Moreover, because the location of the private UEs 230 become known inthe RADIUS server 312 and/or the VLR 320 during the authentication orregistration process, the communication system 200 of the presentinvention has the ability to build or provide services based on locationor location based services.

Coupling between the private UEs 230 and the RADIUS server 312, andbetween the RADIUS server and the public or private HLR 244, 316, can beseen more clearly in FIG. 7. Referring to FIG. 7, the access point 228Ccouples to the RADIUS server 312 via the LAN 229 or via a separate radiolink (not shown) and via an EAP/SIM Link 326, and to the private HLR 316via EAP/RADIUS link 324. In an alternative to the embodiment shown inFIG. 6, the authentication/authorization can be handled by a separateauthentication/authorization server 328 coupled to the private HLR 316via a proprietary link 330, as shown. As indicated previously and asshown in FIG. 7, the private UE 230 must provide authenticationinformation in a manner similar to a GSM MS 212. Generally, this thereare three different ways or methods of accomplishing this, including:(i) use of a universal serial bus (USB) adapter 332 that enables theprivate UE 230 to communicate with a GSM-type SIM card or a 3G-type USIMcard via a USB bus 334; (ii) use of a PCMCIA adapter (not shown) thatenables the private UE 230 to communicate directly with a GSM-type SIMcard; or (iii) use of a virtual SIM as described briefly above and ingreater detail in U.S. patent application Ser. No. 10/002,551.

A preferred embodiment in which the WLAN 128 includes an 802.11 networkwill now be described with reference to FIG. 8. Referring to FIG. 8, thepublic cellular network 104 includes a GSM network 110 and a 3G-network314, as described above. The WLAN 228 includes an 802.11 network havingone or more 802.11 access points 336 (only one of which is shown), andadapted in accordance with the present invention to couple communicationbetween the private UEs 230 and the public network 202 and/or privatecellular network 222. The private UEs 230 can include voicecommunication devices 230A, such as wireless telephones or mobilestations, and data communication devices 230C, such as pagers, facsimilemachines, portable computers, network access appliances and personaldigital assistants (PDAs).

In the 3G-network 214 the 802.11 access point 228C is coupled to the3G-GGSN 270 through the NIB 224 and via an IuPS802.11 interface or link338, the GPRS SGSN 282 through the NIB and via an IuPS802.11 interfaceor link 340, the 3G-RNC 286 through the NIB 224 and via an Iubis802.11interface or link 342, and/or to one or more Node Bs 290 through the NIB224 and via a NodeB802.11 interface or link 344 In the GSM network 210the 802.11 access point 228C can be coupled to the BTS 268 through theNIB 224 and via a BTS802.11 interface or link 346, to the BSC 262through the NIB 224 and via an Abis802.11 interface or link 348, and/orto the MSC 226 through the NIB 224 and via an A802.11 interface or link350 In addition, the WLAN 228 can be coupled to the MSC 256 through theNIB 224 and over the PALIM link 268, described above.

A method or process for operating communication system 100 according toan embodiment of the present invention will now be described withreference to FIG. 9. FIG. 9 is a flowchart showing steps of a method forfacilitating communication between private UEs 230 and the publicnetwork 202 via a WLAN 228. In the method, call information from or toone of a number of private UEs 230 is received in the WLAN 228 (step352). Subscriber identification and security information for the privateUE 230 is provided to the RADIUS system 310 (step 354), and the privateUE is coupled to the public network over the WLAN (step 356). In onepreferred embodiment, the communication between the private UEs 230 andthe public network 202 is voice communication, and the method furtherincludes the step of controlling or accessing supplementary services forthe UE provided by the private cellular network 222 or public network202 service provider (step 358).

As noted above, the subscriber identification and security informationcan be provided from a 3G-type USIM or GSM-type SIM 236 associated witheach private UE 230, or from an identity module 238 in the privatecellular network 222. Moreover, where the identity module 238 of thecommunication system 200 includes a memory system (not shown) havingsubscriber identification and security information stored therein, andthe step of providing subscriber identification and security informationfor the private UE 230 to the RADIUS system 310, step 354, isaccomplished by providing subscriber identification and securityinformation associated with the private UE from the memory system.Alternatively, where the communication system 200 further includes acard holder/reader holding a number of cards associated with the privateUEs 232, and step 354 involves reading subscriber identification andsecurity information stored in one of the number of cards held in thecard holder/reader.

Certain exemplary embodiments of a communication system according to thepresent invention, their uses and advantages will now be described withreference to FIGS. 10 to 16.

FIG. 10 is a block diagram of an embodiment of a communication system200 having a private corporate LAN 360 including a WLAN 228 according tothe present invention, coupled to a public cellular network 204, such asa home public land mobile network (HPLMN), a RADIUS system 310 and anauthentication server 328. Generally in this embodiment, the corporateLAN 360 includes, in addition to the WLAN 228, a hub or router 362coupled through a wired LAN 329 to a number of access points 228A, 228B,228C, in the WLAN and to other terminals, such as computer terminals 342or servers 364. As described above, the RADIUS system 310 includes aRADIUS server or gateway for authorizing access to the communicationsystem 200, and a private HLR (not shown in this figure). Theauthentication server 328 provides or supports roaming capabilities forthe private UEs 230 among the plurality of access points 328A, 328B,228C and the public cellular network 204. The RADIUS system 310communicates with the authentication server 328 to obtain usercredentials and a ciphering key to enable true GSM-type authentication.Preferably, to provide sufficient level of security in the communicationsystem 200 the authentication server 328 uses a GSM A3/A8 algorithm forkey generation. In accordance with the present invention, users of UEs230 can access data in the servers 364, while simultaneouslycommunicating with one another or with other terminals or telephonescoupled to the public cellular network 204. This embodiment provides acentral private HLR (not shown in this figure) in the RADIUS system 310to centralize operation and management (OAM) functions, and to minimizethe changes necessary to the WLAN 228 to access or control supplementaryor value added services and communication with the public cellularnetwork 204 for the private UEs 230. Preferably, the private HLR is ableto handle or serve at least about 100,000 mobile stations, UEs 230 orusers, and the authentication server 328 at least about 200,000, makingthis embodiment particularly suitable for use in airports, hotels,convention centers, etcetera.

FIG. 11 is a block diagram of an alternative embodiment of thecommunication system of FIG. 10, having a number of RADIUS systems 310A,310B or private HLRs and authentication servers 328A, 328B, and NIBs224A, 224B, linked by a PWAN 366 for distributing HLR registration andauthentication loads. This embodiment is particularly suitable for usein enterprises operating a number of different WLANs 228 or corporateLANs 360A, 360B, at a number of different sites. For example, a chain ofhotels, recreational parks or business centers owned and/or operated bya single enterprise.

FIG. 12 is a block diagram of yet another alternative embodiment of thecommunication system of FIG. 10 illustrating roaming of 802.11 or GPRSenabled UEs 230 between a coupled to a home private network 220B, and avisited private network 220B coupled to a visited public cellularnetwork 204B or visited public land mobile network (VPLMN). Referring toFIG. 12 a visiting private UE 230A to an area served by the corporateLAN 260 is able to communicate with another UE 2130B home privatenetwork 220A and terminals or servers 364 in the corporate LAN 360 andwith terminals in the public network 202 through the local or visitedpublic cellular network 204B and the corporate LAN. To authenticate theUE 230A and authorize access to the communication system 200, RADIUSmessages are passed from the visiting UE 230A through the router 360 toa NIB (not shown in this figure) or a RADIUS gateway or server 312 inthe visited private network 220B. The RADIUS server 312 determinessubscriber information for the visiting UE 230A is not stored in privateHLR 216B but in a private HLR 316A in the home private network 220A.RADIUS messages are then passed from the RADIUS server 312 over the PWAN366 to the private HLR 316A and an authentication server 328A in thehome private network 220A of the visiting UE 230A. Note, in thisembodiment each of the distributed private HLRs 316A, 316B, can besmaller, and able to handle fewer mobile stations, UEs 230 or users thanthe HLR in the embodiments described above.

FIG. 13 is a block diagram of yet another embodiment of a communicationsystem 200 according to the present invention, which is particularlysuitable for use in airports, hotels, convention centers, etcetera. Inthis embodiment, a private network or corporate LAN 360 including aRADIUS server 312, a private HLR 316, an authentication server 328, aWLAN 228, and a LAN 229 coupling to servers 364 and access points 228A,228B, 228C, of the WLAN are maintained at a first corporate site orlocation 368. The private network 220 at the first location 368 iscoupled through a router 362 to the Internet 208 and, through a PWAN 366to additional private HLRs 316A, 316B and authentication servers 328A,at additional corporate locations 370. This embodiment provides adistributed HLR and authentication servers, while centralizing OAMfunctions within the PWAN 366, and providing value added services forthe private cellular network 222, and minimizing the changes necessaryto the corporate LAN 360 to enable communication with the publiccellular network (not shown in this figure). Preferably, each of thesmaller distributed HLRs 316, 316A, 316B and authentication servers 328,328A are able to handle or serve at least about 8,000 mobile stations,UEs 230 or users.

FIG. 14 is a block diagram showing communication routing in acommunication system 200 including a WLAN 228 and RADIUS systemaccording to the present invention. Referring to FIG. 14, arrow 372shows the data path for user data from a UE 230 to an IP network, suchas the Internet 208, through an access point 228C of the WLAN 228, LAN229, and a firewall 240. In accordance with the present invention, thesame or additional UEs 230 simultaneously couple to the public cellularnetwork 204 or PLMN through the RADIUS system 310 as shown by arrows374, 376, and 378. In particular, arrows 374 and 376 show a signalingpath over which RADIUS messages are passed to identify the UE 230 andauthorize access to the communication system 200. Arrow 378 shows thepath of user data over which data, including voice, graphics or images,and other data is passed between the UE 230 and the public cellularnetwork 204.

FIG. 15 is a block diagram of yet another embodiment of a communicationsystem 200 showing an architecture of the communication system accordingto the present invention. Referring to FIG. 15 the core element of thecommunication system 200 is the NIB 224, which combines an MSC 396, aGSM/GPRS radio 398, a private HLR 316 and private VLR 318. The MSC 396couples to the GSM/GPRS radio 398 through an interface 400, and to theprivate HLR 316 and private VLR 318 through a VRAD interface 322. TheNIB 224 couples to a WLAN access points 228C through an EAP link,thereby enabling the NIB to full functional GSM/GPRS cellularcapabilities as well as extending GSM/GPRS type security and roamingcapabilities to UEs 230 over the WLAN 228. WLAN clients or UEs 230capable of accessing the services provided through the NIB 224,generally include a LAN PC card 402 to enable wireless access, aGSM-type SIM 234, a client software or driver 404 to enable the UE toemulate a communication terminal and/or to control supplementary serviceprovided by the communication system 200, and an underlying operatingsystem 406.

The NIB 224 couples to a network management center (NMC) or RADIUSserver 312 through the VRAD 322. In the embodiment shown, the RADIUSserver 312 includes an operations maintenance center (OMC 408), RADIUSproxy function 410, and an underlying operating system 412. The RADIUSserver 312 also couples to the WLAN access points 228C through an 802.11over RADIUS link, thereby enabling the RADIUS server to authorize andcontrol access to the communication system 200.

The NIB 224 also couples to a subscriber management graphical userinterface (SMGUI 414) to allow management of the communication system200 and the subscriber profiles maintained in the private HLR 316 andprivate VLR 318. The SMGUI 414 generally includes a serviceconfiguration function 416 for management of communication systemconfiguration, a service management function 418 for management ofsubscriber profiles, and an underlying operating system 420.

The RADIUS server 312 couples via an IP network or link to other remoteRADIUS servers 312B, and through the remote RADIUS servers to other GSMnetworks or PLMN 204. The RADIUS server 312 couples via an IP network orlink to a billing server 422 or service. This particularly useful forforwarding billing information on roaming or visiting UEs 230.

The WLAN access points 228C are further coupled to an IP network, suchas LAN 229, and through the LAN to the Internet 208, an enterprisenetwork 424, and various WLAN services 426.

Some of the important aspects of the present invention will now berepeated to further emphasize their structure, function and advantages.

It will be appreciated that WLAN standards, such as IEEE 802.1X,HiperLAN/1 or HiperLAN/2, HiperMAN, and BRAN, can be used to deriveauthentication and encryption keys for use with any cipher, and can alsobe used to periodically refresh keys and re-authenticate so as to makesure that the keying material is fresh. These standards do not specify asingle authentication method; rather they utilize ExtensibleAuthentication Protocol (EAP) as its authentication framework. Thisallows WLAN enabled access points 228 to support a wide range ofauthentication methods, including certificate-based authentication,smartcards, token cards, one-time and passwords. Moreover, sinceswitches and access points 228A, 228B, 228C, act as a pass-through forEAP, new authentication methods can be added without the need to upgradethe switch or access point, by adding software on the host and back-endauthentication server 328.

A major advantage of using an WLAN based authentication scheme is thatthe access control capability is built into each access point 228A,228B, 228C. An 802.11 enabled access point 228A, 228B, 228C, candirectly communicate with a RADIUS system 310 or server 312 toauthenticate a user or UE 230 and generate encryption key for thesession. The access point 228A, 228B, 228C, can also store billingrecords for the subscriber and transfer them to the RADIUS system 310using the RADIUS accounting protocol. The WLAN 228 based approach can beused to provide access to the Internet 208 in both wired LANs 229 aswell as WLANs 228 operated by a service provider. Also, the client partof the network can be greatly simplified by using authenticationfunctions for WLAN 228 based on WLANs built into many operating systems,such as the Windows XP® operating system, commercially available fromMicrosoft, Inc.

Another advantage of a communication system 200 according to the presentinvention is that the cellular service provider or service providerneeds only to install a limited number of WLAN-enabled access points228A, 228B, 228C, in the served areas, each access point directlycommunicating with a RADIUS system 310 or server 312. The use of EAP andWLAN-standards provides the required security in message exchangebetween the access point 228A, 228B, 228C, and the RADIUS system.

Yet another advantage is that EAP allows different authenticationmethods to be used by the authentication server 328 based uponconfiguration of the RADIUS system 310 and/or the authentication server.Thus, a cellular service provider can employ SIM based authentication tointegrate 802.11 access information with a GSM user profile. A draftproposal outlining SIM based authentication using EAP, entitled EAP SIMauthentication, is available from the Internet Engineering Task Force(IETF), and is incorporated herein by reference.

In one embodiment, an EAP interface 322 to a RADIUS server 312 is addedto a VLR 320 in a NIB 224. This will allow authentication credentials tobe exchanged between the WLAN 228 client UE 230 and a private HLR 316following a GSM based authentication, encapsulated in EAP. The privateHLR 316 will also be able to supply the access point 228A, 228B, 228C,with any user specific information, such as subscription profile,quality of service (QoS), etcetera, to enable any servicedifferentiation.

In another embodiment, compact SIM card readers 332 which connect via aUSB bus 334 to a UE 230, such as a personal computer (PC) or a laptopcomputer, can be used to support for SIM based authentication at clientend. For example, an obtain/write interface layer between a WLAN driverof a Windows® based computer and the SIM card reader 332 allowsauthentication credentials to be generated and exchanged between the SIMand the access point 228A, 228B, 228C.

In still another embodiment, support for WLAN-session key generation canbe accomplished using an algorithm similar to GSM ciphering keygeneration to ensure the WLAN solution offers a level of security closeto that offered in GSM.

In yet another embodiment, inter-working capability between RADIUS basedaccounting and current GSM call data records or CDRs is accomplished byuse of a separate accounting server (not shown). This accounting serverreceives the RADIUS accounting data from the access points 228A, 228B,228C, converts the data into GSM based CDRs, for example, based uponsubscriber profile, and transfers it to the billing entity using filetransfer protocol (FTP).

In another embodiment, the communication system 200 according to thepresent invention has the ability to support roaming of WLAN 228 UEs 230based upon a RADIUS/DIAMETER roaming model along with traditional GSMsubscriber roaming based upon MAP. Requirements for different UEs 230,such as an 802.11 network access platform, include subscription to aWLAN service offered by a carrier. Generally, the user or subscriberwould access the service provider's network through a WLAN enabledclient device or UE 230, such as a laptop computer. Preferably, theclient computer's operating system includes WLAN support, eithernatively or through additional drivers or an emulator program downloadedfrom the service provider, as described above. Two known operatingsystems satisfying this requirement are Microsoft Windows 2000® andMicrosoft Windows XP®.

The UE 230 could authenticate in way similar to that of a GSM mobilestation. There are several feasible methods of achieving this. In onemethod the UE 230 will need an authentication driver to interface with aGSM-type SIM card 234. This can be accomplished either through the useof a PCMCIA adapter or a USB adapter 332 that provides the ability forthe UE 230 to communicate with the GSM-type SIM card 234. A USB adapter332 being more compact and reasonably priced than the PCMCIA adapter, itis the preferred interface. To emulate GSM authentication on the WLANsecurity framework, an EAP extension module or interface 322 isrequired. The EAP interface 322 will communicate with GSM-type SIM card234 using an application programming interface (API), such as a PCSmartcard (PC/SC) interface, obtained from the service provider andplugged into the UE 230 as a dynamic linked library file (DLL).

The generation and use of session key for encryption of WLAN packets inconventional WLANs generally follows vendor specific interfaces. Thus,session key for encryption of WLAN packets depend on vendorspecifications. In a preferred embodiment, in the communication systemof the present invention the encryption key is generated based upon oneor more ciphering key (Kc) generated during EAP/GSM authentication.

The access points 228A, 228B, 228C, required to work with thecommunication system 200 of the present invention must contain WLANbased authentication and session encryption support. The access pointpoints 228A, 228B, 228C, will also be required to act as a RADIUS clientto the RADIUS system 310 or server 312 and as a Network Access Server(NAS) in user authentication processes, causing EAP messages to beexchanged via RADIUS messaging. Two vendors offering access points 228A,228B, 228C, meeting the above specifications include Proxim Inc., ofSunnyvale, Calif., and Cisco Inc., of San Jose, Calif.

In addition to the above, preferably the communication system 200further includes a RADIUS server 312 capable of performing followingfunctions:

-   -   Interface with the access points 228A, 228B, 228C, for        authentication of private UEs 230, through interpretation of        either a Username field or a EAP User Identity field in the        RADIUS authentication request 398.    -   Route the authentication request to the appropriate        authentication server 328.    -   Act as a proxy to the public HLR/VLR 244 or to an external        RADIUS system 310 or private HLR 316 if roaming is enabled, by        routing of user authentication request to the appropriate HLR        based upon information contained in the Username field.    -   Where the public or private HLR 244, 316, is a central HLR, the        RADIUS Server 212 will act as a proxy to forward authentication        request to the HLR.    -   Where the public or private HLR 244, 316, is a distributed HLR,        the RADIUS Server 312 could be adapted to contact the correct        HLR in either of the following ways:

1. Query a standalone Central Address Table (CAT) Server (not shown) tomatch the HLR corresponding to subscriber IMS1; or

2. Use a configuration table (not shown) that matches IMSI ranges of theUE 230 with the controlling HLR. (This model works if IMS1 partitioningis implicitly or explicitly enabled for subscriber provisioning acrossmultiple HLRs)

-   -   Receive RADIUS accounting packets generated by different access        points 128A, 128B, 128C.    -   Forward accounting packets to a billing server (not shown)        through a EAP interface 222.    -   Forward a copy of the accounting packets to the UE 230 home        RADIUS server 312 or accounting server for the case of roaming        subscribers.

Preferably, the RADIUS or private HLR 316 supports all of the followingattributes or capabilities:

-   -   Ability to enable/Disable WLAN 228 access for a particular UE        230, based upon subscriber IMSI.    -   Ability to re-authenticate the subscriber with the WLAN 228 upon        timer the session timer expiry at the access point 228A, 228B,        228C. (Session timeout value)    -   Ability to use an algorithm to authenticate a subscriber to the        WLAN 228. (Authentication algorithm)    -   Ability to notify the user with an operator defined message with        appropriate text whenever WLAN access or authentication is        attempted. (Notification message)    -   Ability to specify the maximum inactivity time after which the        UE 230 will be assumed to wandered from out of the range of        access point 228A, 228B, 228C, and removed from active user        list. (Idle Timeout)    -   Ability to specify the maximum number of consecutive failed        authentication attempts before the UE 230 will be disabled from        WLAN access. (Retry limit)

More preferably, the RADIUS or private HLR 316 of the communicationsystem 200 will support following Read-only attributes:

-   -   Ability to store information about the MAC address of the UE 230        used by the subscriber to access WLAN 228. (Calling Station Id)    -   Ability to provide the date and time when last authentication        attempt was made on WLAN 228. (Last Access Time)    -   Ability to provide the date and time when last successful WLAN        228 authentication happened for the UE 230. (Last Successful        access time)    -   Ability to provide other miscellaneous connection information        passed by the access point 228A, 228B, 228C, e.g., connected on        802.11b at 10 MBPS etc. (Connect Information)

As noted above, the RADIUS or private HLR 216 will communicate with theRADIUS server 312 using an EAP interface only. This will avoid use,creation and maintenance of a proprietary protocol between RADIUS serverand the HLR. To support the EAP interface 322:

-   -   An MD5 algorithm is implemented to verify the identity of the        RADIUS server 312 acting as proxy to the public or private HLR,        and to derive the user information from the encrypted message.    -   The EAP interface listens on well-known RADIUS server port, and        processes only those RADIUS messages that contain EAP attributes        to perform an EAP authentication (Identity request, access        challenge(s), EAP success or failure) procedure to complete user        authentication    -   Frames RADIUS access accept message with all the useful WLAN        subscriber profile information provisioned at the public or        private HLR.

Finally, in one embodiment, a subscriber management user interface(SMGUI 414) is provided to allow provisioning of the WLAN 228 serviceattributes including, for example, display of read-only attributes ofthe communication system 200. In one version of this embodiment, thedisplay of the SMGUI 414 could be auto refreshed using an asynchronousmechanism with the private HLR 316. Alternatively, for simplicity ofimplementation, a refresh button on the SMGUI 414 could be used to getupdates from the private HLR 316.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical application,to thereby enable others skilled in the art to best use the inventionand various embodiments with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto and theirequivalents.

The present disclosure is written for ease of understanding by those ofskill in the art. For others, the following documents, incorporatedherein by reference for all purposes, may be reviewed for additionalinformation.

Local and Metropolitan Area Networks, IEEE Standard for Wireless LANMedium Access Control (MAC) and Physical Layer (PHY) specifications,IEEE Std. 802.11-1997, pp. 34-59 and pp. 123-128

“HiperLAN: The High Performance Radio Local Area Network Standard”, byG. A. Halls, Elec. & Comm. Eng. Journal, Dec. 1994, pp. 289-296

1. A communication system for providing voice and data communicationbetween a public network and a plurality of user equipment terminals(UEs) at a plurality of locations, the communication system comprising:a community wireless local area network (WLAN) comprising fixedequipment that includes: a centralized base transceiver station (CBTS)coupled to the public network; and a plurality of remote transceiverstations (RTSs) each coupled to a number of the plurality of UEs, and,via a radio link, to the CBTS, whereby the voice and data communicationis provided between the public network and the plurality of UEs; whereinat least one of the RTSs is located at each of the plurality oflocations; and wherein the CBTS and each RTS comprises a respectiveGlobal Systems for Mobile communication/General Packet Radio Service(GSM/GPRS) transceiver for communications therebetween in order toprovide data communication between the public network and the pluralityof UEs; wherein respective GSM/GPRS radio frequency signals transmittedby the CBTS to the RTSs and by each RTS to the CBTS are frequencyconverted from respective first frequencies within conventional GSMfrequency bands to respective second frequencies above the conventionalGSM frequency bands; and wherein the respective frequency-convertedGSM/GPRS radio frequency signals received by the CBTS from the RTSs andby each RTS from the CBTS are frequency converted from respective secondfrequencies above the conventional GSM frequency bands to respectivefirst frequencies within the conventional GSM frequency bands.
 2. Thecommunication system according to claim 1, wherein the public networkcomprises a public switched telephone network and an Internet, andwherein the CBTS is coupled to the public network via a trunk.
 3. Thecommunication system according to claim 1, wherein the CBTS and each RTSfurther comprises a WLAN transceiver to provide voice communicationbetween the public network and the plurality of UEs.
 4. Thecommunication system according to claim 3, wherein the WLAN transceiveris compatible with an open standard protocol selected from a groupconsisting of: High Performance Local Area Network (HiperLAN/1); HighPerformance Local Area Network (HiperLAN/2); and Institute of Electricaland Electronics Engineers 802.11 (IEEE 802.11).
 5. The communicationsystem according to claim 1, wherein the CBTS and each of the pluralityof RTSs includes a frequency converter.
 6. The communication systemaccording to claim 1, wherein the public network comprises a publicswitched telephone network and the Internet, and wherein the CBTS iscoupled to the public network via a public wireless network.
 7. A systemcomprising: a centralized base transceiver station (CBTS) coupled to apublic network; and a plurality of remote transceiver stations (RTSs),each coupled to a plurality of user equipment terminals (UEs) at aplurality of locations, and, via a radio link, to the CBTS; wherein atleast one of the RTSs is located at each of the plurality of locations;and wherein the CBTS and each RTS comprises: a respective Global Systemsfor Mobile communication (GSM) transceiver that transmits and receivesGSM radio frequency signals at frequencies within conventional GSMfrequency bands; and a respective frequency converter; whereinrespective GSM radio frequency signals transmitted by the CBTS to theRTSs and by each RTS to the CBTS are frequency converted by therespective frequency converter from respective first frequencies withinconventional GSM frequency bands to respective second frequencies abovethe conventional GSM frequency bands; and wherein the respectivefrequency-converted GSM radio frequency signals received by the CBTSfrom the RTSs and by each RTS from the CBTS are frequency converted bythe respective frequency converter from respective second frequenciesabove the conventional GSM frequency bands to respective firstfrequencies within the conventional GSM frequency bands.
 8. The systemaccording to claim 7, wherein each GSM transceiver is adapted tocommunicate using GSM technology at a frequency band within (ETSI)specification.
 9. The system according to claim 8, wherein each GSMtransceiver is adapted to communicate using GSM technology at afrequency band of at least about 3.5 Ghz.
 10. The system according toclaim 7, wherein each GSM transceiver is a respective GSM/General PacketRadio Service (GSM/GPRS) transceiver, and wherein the CBTS and each RTSis adapted to communicate data.
 11. In a communication system includinga community wireless local area network (WLAN) comprising fixedequipment that includes a centralized base transceiver station (CBTS)coupled to a public network, and a plurality of remote transceiverstations (RTSs) each coupled to a number of a plurality of UserEquipment terminals (UEs) located at a plurality of locations, and, viaa radio link, to the CBTS, a method of providing voice and datacommunication between the plurality of UEs and the public network, themethod comprising: receiving call information in the community WLAN;providing subscriber identification and security information for the UEto the community WLAN using at least one of the RTSs; and coupling theUE to the public network over the community WLAN, wherein coupling theUE to the public network comprises coupling the CBTS to the RTS via aradio link using a GSM standard; wherein at least one of the RTSs islocated at each of the plurality of locations; wherein the CBTS and eachRTS comprises a respective Global Systems for Mobilecommunication/General Packet Radio Service (GSM/GPRS) transceiver forcommunications therebetween; wherein respective GSM/GPRS radio frequencysignals transmitted by the CBTS to the RTSs and by each RTS to the CBTSare frequency converted from respective first frequencies withinconventional GSM frequency bands to respective second frequencies abovethe conventional GSM frequency bands; and wherein the respectivefrequency-converted GSM/GPRS radio frequency signals received by theCBTS from the RTSs and by each RTS from the CBTS are frequency convertedfrom respective second frequencies above the conventional GSM frequencybands to respective first frequencies within the conventional GSMfrequency bands.
 12. The method according to claim 11, wherein thepublic network comprises a public switched telephone network and anInternet, and wherein the step of coupling the UE to the public networkcomprises the step of coupling the CBTS to the public network via atrunk.
 13. The method according to claim 11, wherein the CBTS and eachRTS further comprises a WLAN transceiver, and wherein the step ofcoupling the UE to the public network comprises the step of coupling theCBTS to the RTS using a WLAN standard to provide voice communicationbetween the public network and the plurality of UEs.
 14. The methodaccording to claim 13, wherein the WLAN standard is an open standardprotocol selected from a group consisting of: High Performance LocalArea Network (HiperLAN/1); High Performance Local Area Network(HiperLAN/2); and Institute of Electrical and Electronics Engineers802.11 (IEEE 802.11).
 15. The method according to claim 11, wherein thepublic network comprises a public switched telephone network and theInternet, and wherein the step of coupling the UE to the public networkcomprises the step of coupling the CBTS to the public network via apublic wireless network.